Among the majority of bird species males and females breed in monogamous pairs, and it is not uncommon for these pairs to remain stable throughout the reproductive lives of the animals. Moreover, both sexes are often heavily committed to the parental care of the young. For instance, in the ring dove both male and female construct the nest, incubate the eggs, and care for squabs. The contributions of the two sexes are not merely additive; they complement one another in an exquisitely tuned division of labor. The complexity of this relationship confronts us with several challenging questions: 1) To what extent are the basic physiological (e.g., hormonal) changes which carry the male and female through the various stages of the breeding cycle similar or different in the two sexes, and how are they synchronized? 2) Since ring doves develop a preference for particular individuals as mates and since such individual attachments increase the breeding efficiency and productivity of the pair, what factors promote the establishment and maintenance of these social relationships? 3) Because the male invests himself so heavily in parental care, what tactics does he use to ensure that the young produced are, in fact, his own genetic offspring?